/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.iotdb.db.protocol.rest.filter;

import org.apache.iotdb.common.rpc.thrift.TSStatus;
import org.apache.iotdb.commons.auth.AuthException;
import org.apache.iotdb.commons.auth.authorizer.IAuthorizer;
import org.apache.iotdb.db.auth.AuthorizerManager;
import org.apache.iotdb.db.conf.rest.IoTDBRestServiceConfig;
import org.apache.iotdb.db.conf.rest.IoTDBRestServiceDescriptor;
import org.apache.iotdb.db.protocol.rest.model.ExecutionStatus;
import org.apache.iotdb.rpc.TSStatusCode;
import org.glassfish.jersey.internal.util.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.annotation.WebFilter;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.ext.Provider;
import java.io.IOException;

@WebFilter("/*")
@Provider
public class AuthorizationFilter implements ContainerRequestFilter {

    private static final Logger LOGGER = LoggerFactory.getLogger(AuthorizationFilter.class);

    private final IAuthorizer authorizer = AuthorizerManager.getInstance();
    private final UserCache userCache = UserCache.getInstance();
    IoTDBRestServiceConfig config = IoTDBRestServiceDescriptor.getInstance().getConfig();

    public AuthorizationFilter() throws AuthException {
    }

    @Override
    public void filter(ContainerRequestContext containerRequestContext) throws IOException {
        if ("OPTIONS".equals(containerRequestContext.getMethod())
                || "ping".equals(containerRequestContext.getUriInfo().getPath())
                || (config.isEnableSwagger()
                && "swagger.json".equals(containerRequestContext.getUriInfo().getPath()))) {
            return;
        } else if (!config.isEnableSwagger()
                && "swagger.json".equals(containerRequestContext.getUriInfo().getPath())) {
            Response resp =
                    Response.status(Status.NOT_FOUND).type(MediaType.APPLICATION_JSON).entity("").build();
            containerRequestContext.abortWith(resp);
            return;
        }

        String authorizationHeader = containerRequestContext.getHeaderString("authorization");
        if (authorizationHeader == null) {
            Response resp =
                    Response.status(Status.UNAUTHORIZED)
                            .type(MediaType.APPLICATION_JSON)
                            .entity(
                                    new ExecutionStatus()
                                            .code(TSStatusCode.INIT_AUTH_ERROR.getStatusCode())
                                            .message(TSStatusCode.INIT_AUTH_ERROR.name()))
                            .build();
            containerRequestContext.abortWith(resp);
            return;
        }
        User user = userCache.getUser(authorizationHeader);
        if (user == null) {
            user = checkLogin(containerRequestContext, authorizationHeader);
            if (user == null) {
                return;
            } else {
                userCache.setUser(authorizationHeader, user);
            }
        }

        BasicSecurityContext basicSecurityContext =
                new BasicSecurityContext(
                        user, IoTDBRestServiceDescriptor.getInstance().getConfig().isEnableHttps());
        containerRequestContext.setSecurityContext(basicSecurityContext);
    }

    private User checkLogin(
            ContainerRequestContext containerRequestContext, String authorizationHeader) {

        String decoded = Base64.decodeAsString(authorizationHeader.replace("Basic ", ""));
        // todo: support special chars in username and password
        String[] split = decoded.split(":");
        if (split.length != 2) {
            Response resp =
                    Response.status(Status.BAD_REQUEST)
                            .type(MediaType.APPLICATION_JSON)
                            .entity(
                                    new ExecutionStatus()
                                            .code(TSStatusCode.ILLEGAL_PARAMETER.getStatusCode())
                                            .message("Illegal format of authorization header."))
                            .build();
            containerRequestContext.abortWith(resp);
            return null;
        }

        User user = new User();
        user.setUsername(split[0]);
        user.setPassword(split[1]);
        TSStatus tsStatus = ((AuthorizerManager) authorizer).checkUser(split[0], split[1]);
        if (tsStatus.code != 200) {
            Response resp =
                    Response.status(Status.UNAUTHORIZED)
                            .type(MediaType.APPLICATION_JSON)
                            .entity(
                                    new ExecutionStatus()
                                            .code(TSStatusCode.WRONG_LOGIN_PASSWORD.getStatusCode())
                                            .message(TSStatusCode.WRONG_LOGIN_PASSWORD.name()))
                            .build();
            containerRequestContext.abortWith(resp);
            return null;
        }
        return user;
    }
}
